用ZigBee绿色电源设计超低功耗无线自动化

　　用ZigBee绿色电源设计超低功耗无线自动化

　　新的协议和基准将促进从环境中获取能量的超低功耗无线系统的发展。ZigBee联盟提供的绿色电力规范允许使用低占空比的无线系统，并能从周围获得机械、热能或太阳能。

　　一种新的ZigBee规范称为绿色能源现在支持低成本的能源收集和超长的电池寿命为ZigBee无线应用的智能家居，而一个行业集团正在寻找基准超低功耗设备。

　　在ZigBee Pro 2012的绿色电源功能提供免费电池，能量收集设备的能力，加入任何绿色电源启用ZigBee网络。不需要电池，自给设备通常只收获足够的能量来传送机械、热能或射频能量的简短指令。例如，没有电池的电灯开关会从开关上获得能量。这种能量被捕获，以向网络发送“接通”或“关闭”命令，以接通或关闭适当的光，因此，自供电的电灯开关可以位于房间的任何地方，而无需运行电源线。

　　However， the discussion on the performance of devices now moves from the current and power consumption to the overall energy consumed by the system. At these low levels of microjoules， there is no standardized way to evaluate different systems， so new benchmarks are also being developed separately that will give engineers key information about the performance of the microcontrollers and wireless systems that are used in these home automation installations.

　　Adapting the ZigBee protocol is a lower power approach than using other approaches. A typical Wi-Fi card in a laptop PC uses roughly 2 kJ of energy in an hour （assuming a 200 mA， 3 V transceiver runs continuously）。 In comparison， a 30 W lamp on for an hour consumes 100 kJ， 50 times as much. The ZigBee set-top box remote control using the R4CE protocol uses just 20 mJ per hour， a factor of 100，000 times less than the Wi-Fi card.